Hinchcliffe explained some of the thinking behind the introduction of Leela. He wanted to create a Doctor-companion relationship similar to that between Eliza Doolittle and Professor Henry Higgins in the play Pygmalion.

Mat Irvine described how the carved face of the Fourth Doctor was created, with Tom Baker coming to the studio and being coated is plaster, while he had straws up his nose to allow him to breathe.